$\qquad \qquad h = 2a+20.5$ <br>A Pediatrician uses the model above to estimate the height $h$ of a boy, in inches, in terms of the boy's age 'a' in years, between the ages of 5 and 10. Based on the model, what is the estimated increase in inches of a boy's height each year ?

Question

$\begin{array}{1 1} (a)\; 1 \\ (b)\; 2 \\ (c)\;3 \\(d)\;3.5 \end{array}$